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authorAndrew Waterman <andrew@sifive.com>2022-10-20 13:35:13 -0700
committerAndrew Waterman <andrew@sifive.com>2022-10-20 13:35:13 -0700
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tree9868854fc22c6958b64e4ac30ac4559dde8ba094
parentd25c67b482ffc46055d3201f38db94c1534f7602 (diff)
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Specify which instructions are affected by Zamzam
-rw-r--r--src/zam.tex12
1 files changed, 8 insertions, 4 deletions
diff --git a/src/zam.tex b/src/zam.tex
index 085ab51..16818f2 100644
--- a/src/zam.tex
+++ b/src/zam.tex
@@ -5,7 +5,11 @@
accepted as standard by RISC-V International.}
This chapter defines the ``Zam'' extension, which standardizes atomicity
-guarantees for misaligned memory accesses.
+guarantees for certain misaligned memory accesses.
+
+\begin{commentary}
+The Zam extension does not alter the specification of aligned memory accesses.
+\end{commentary}
The Zam extension defines the concept of ``misaligned atomicity granule''
(MAG), an aligned power-of-two number of bytes within which a misaligned
@@ -31,6 +35,6 @@ multiple MAGs must raise an exception, whereas regular loads and
stores may either raise an exception or proceed non-atomically.
\end{commentary}
-\begin{commentary}
-The Zam extension does not alter the specification of aligned memory accesses.
-\end{commentary}
+The Zam extension affects only the memory-access instructions defined in the
+base ISAs and the A, F, D, Q, C, Zcb, Zfh, and hypervisor extensions, and only
+those memory accesses no wider than XLEN bits.